Vibration of cylindrical shells with and without ring-stiffening

The dynamical response of two cylindrical shells, one with and one without ring‐stiffening, was investigated. Particular attention was placed on the use of ring‐stiffening to provide velocity insertion loss at the point of excitation. The driving‐point admittance was measured and compared with predictions using the mean‐value characteristic admittance method [E. Skudrzyk, J. Acoust. Soc. Am. 51, 98 (1972)]. This method predicts the geometric‐mean of the response of a vibrator with respect to frequency; and is valid at low as well as high frequencies. The basic computations involve the mode masses and mode density. The measurements were in good agreement with the theory, and demonstrate that mean‐value characteristic admittance method is a practical means of predicting the vibrational response of shell structures to point excitation. [Work performed at the Physics Department of The Pennsylvania State University and supported by the Office of Naval Research under contract number 474.]